com.sun.media.jai.codec
Class TIFFDirectory

java.lang.Object
  |
  +--com.sun.media.jai.codec.TIFFDirectory

All Implemented Interfaces:

Serializable

public class TIFFDirectory

extends Object

implements Serializable

A class representing an Image File Directory (IFD) from a TIFF 6.0 stream. The TIFF file format is described in more detail in the comments for the TIFFDescriptor class.

A TIFF IFD consists of a set of TIFFField tags. Methods are provided to query the set of tags and to obtain the raw field array. In addition, convenience methods are provided for acquiring the values of tags that contain a single value that fits into a byte, int, long, float, or double.

Every TIFF file is made up of one or more public IFDs that are joined in a linked list, rooted in the file header. A file may also contain so-called private IFDs that are referenced from tag data and do not appear in the main list.

This class is not a committed part of the JAI API. It may be removed or changed in future releases of JAI.

See Also:

TIFFDescriptor, TIFFField, Serialized Form

Constructor Summary

TIFFDirectory(SeekableStream stream, int directory)
Constructs a TIFFDirectory from a SeekableStream.

TIFFDirectory(SeekableStream stream, long ifd_offset, int directory)
Constructs a TIFFDirectory by reading a SeekableStream.

Method Summary

TIFFField	getField(int tag) Returns the value of a given tag as a TIFFField, or null if the tag is not present.
byte	getFieldAsByte(int tag) Returns the value of index 0 of a given tag as a byte.
byte	getFieldAsByte(int tag, int index) Returns the value of a particular index of a given tag as a byte.
double	getFieldAsDouble(int tag) Returns the value of index 0 of a given tag as a double.
double	getFieldAsDouble(int tag, int index) Returns the value of a particular index of a given tag as a double.
float	getFieldAsFloat(int tag) Returns the value of index 0 of a given tag as a float.
float	getFieldAsFloat(int tag, int index) Returns the value of a particular index of a given tag as a float.
long	getFieldAsLong(int tag) Returns the value of index 0 of a given tag as a long.
long	getFieldAsLong(int tag, int index) Returns the value of a particular index of a given tag as a long.
TIFFField[]	getFields() Returns an array of TIFFFields containing all the fields in this directory.
long	getIFDOffset() Returns the offset of the IFD corresponding to this TIFFDirectory.
long	getNextIFDOffset() Returns the offset of the next IFD after the IFD corresponding to this TIFFDirectory.
static int	getNumDirectories(SeekableStream stream) Returns the number of image directories (subimages) stored in a given TIFF file, represented by a SeekableStream.
int	getNumEntries() Returns the number of directory entries.
int[]	getTags() Returns an ordered array of ints indicating the tag values.
boolean	isBigEndian() Returns a boolean indicating whether the byte order used in the the TIFF file is big-endian (i.e.
boolean	isTagPresent(int tag) Returns true if a tag appears in the directory.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TIFFDirectory

public TIFFDirectory(SeekableStream stream,
                     int directory)
              throws IOException

Constructs a TIFFDirectory from a SeekableStream. The directory parameter specifies which directory to read from the linked list present in the stream; directory 0 is normally read but it is possible to store multiple images in a single TIFF file by maintaing multiple directories.

Parameters:

stream - a SeekableStream to read from.

directory - the index of the directory to read.

TIFFDirectory

public TIFFDirectory(SeekableStream stream,
                     long ifd_offset,
                     int directory)
              throws IOException

Constructs a TIFFDirectory by reading a SeekableStream. The ifd_offset parameter specifies the stream offset from which to begin reading; this mechanism is sometimes used to store private IFDs within a TIFF file that are not part of the normal sequence of IFDs.

Parameters:

stream - a SeekableStream to read from.

ifd_offset - the long byte offset of the directory.

directory - the index of the directory to read beyond the one at the current stream offset; zero indicates the IFD at the current offset.

Method Detail

getNumEntries

public int getNumEntries()

Returns the number of directory entries.

getField

public TIFFField getField(int tag)

Returns the value of a given tag as a TIFFField, or null if the tag is not present.

Note that the value (data) of the TIFFField will always be the actual field value regardless of the number of bytes required for that value. This is the case despite the fact that the TIFF IFD Entry corresponding to the field may actually contain the offset to the field's value rather than the value itself (the latter occurring if and only if the value fits into 4 bytes). In other words, the value of the field will already have been read from the TIFF stream.

isTagPresent

public boolean isTagPresent(int tag)

Returns true if a tag appears in the directory.

getTags

public int[] getTags()

Returns an ordered array of ints indicating the tag values.

getFields

public TIFFField[] getFields()

Returns an array of TIFFFields containing all the fields in this directory.

getFieldAsByte

public byte getFieldAsByte(int tag,
                           int index)

Returns the value of a particular index of a given tag as a byte. The caller is responsible for ensuring that the tag is present and has type TIFFField.TIFF_SBYTE, TIFF_BYTE, or TIFF_UNDEFINED.

getFieldAsByte

public byte getFieldAsByte(int tag)

Returns the value of index 0 of a given tag as a byte. The caller is responsible for ensuring that the tag is present and has type TIFFField.TIFF_SBYTE, TIFF_BYTE, or TIFF_UNDEFINED.

getFieldAsLong

public long getFieldAsLong(int tag,
                           int index)

Returns the value of a particular index of a given tag as a long. The caller is responsible for ensuring that the tag is present and has type TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT, TIFF_SSHORT, TIFF_SLONG or TIFF_LONG.

getFieldAsLong

public long getFieldAsLong(int tag)

Returns the value of index 0 of a given tag as a long. The caller is responsible for ensuring that the tag is present and has type TIFF_BYTE, TIFF_SBYTE, TIFF_UNDEFINED, TIFF_SHORT, TIFF_SSHORT, TIFF_SLONG or TIFF_LONG.

getFieldAsFloat

public float getFieldAsFloat(int tag,
                             int index)

Returns the value of a particular index of a given tag as a float. The caller is responsible for ensuring that the tag is present and has numeric type (all but TIFF_UNDEFINED and TIFF_ASCII).

getFieldAsFloat

public float getFieldAsFloat(int tag)

Returns the value of index 0 of a given tag as a float. The caller is responsible for ensuring that the tag is present and has numeric type (all but TIFF_UNDEFINED and TIFF_ASCII).

getFieldAsDouble

public double getFieldAsDouble(int tag,
                               int index)

Returns the value of a particular index of a given tag as a double. The caller is responsible for ensuring that the tag is present and has numeric type (all but TIFF_UNDEFINED and TIFF_ASCII).

getFieldAsDouble

public double getFieldAsDouble(int tag)

Returns the value of index 0 of a given tag as a double. The caller is responsible for ensuring that the tag is present and has numeric type (all but TIFF_UNDEFINED and TIFF_ASCII).

getNumDirectories

public static int getNumDirectories(SeekableStream stream)
                             throws IOException

Returns the number of image directories (subimages) stored in a given TIFF file, represented by a SeekableStream.

isBigEndian

public boolean isBigEndian()

Returns a boolean indicating whether the byte order used in the the TIFF file is big-endian (i.e. whether the byte order is from the most significant to the least significant)

getIFDOffset

public long getIFDOffset()

Returns the offset of the IFD corresponding to this TIFFDirectory.

getNextIFDOffset

public long getNextIFDOffset()

Returns the offset of the next IFD after the IFD corresponding to this TIFFDirectory.